Threaded fasteners are used for many applications and must be transported during manufacture and use. During transit and processing, threaded fasteners may become damaged. For example, within a large batch of threaded fasteners, a small number of threaded fasteners may suffer thread damage as they come into contact with other fasteners or with handling equipment. The use of damaged threaded fasteners can result in a defective and potentially unsafe product.
Damaged threaded fasteners are particularly costly for automobile manufacturers. Assembly of automobile engines relies upon threaded fasteners to seal critical engine components. The use of damaged threaded fasteners can result in an improperly sealed engine that is prone to fluid leaks. Automobile manufacturers and suppliers implement post production inspection equipment to locate defective parts such as threaded fasteners. However, post production removal of fasteners is expensive as the engine may need to be disassembled and reassembled. As such, it is desirable to locate defective fasteners prior to assembly.
One inspection technique currently used is a manual inspection of each threaded fastener prior to its use within part assembly. This technique suffers from many problems. Notably, this technique is very expensive, slow, and suffers from human error.
A second inspection technique currently used involves the use of a camera to photograph the threads of a threaded fastener. One problem with this approach is that the camera is unable to capture the entire thread of the threaded fastener. Only a single profile is generally observed. If a thread defect is oriented away from the photographic range of the camera, it will remain undetected.
Accordingly, what is needed in the art are systems and methods for identifying damaged threaded fasteners prior to incorporation into an assembled product.